1. Field of the Invention
The present invention generally relates to methods and systems for investigating plasmas. In particular, aspects of the invention relate to detecting changes in fluorescence of a plasma due to terahertz radiation to analyze plasmas.
2. Description of Related Art
In the field of plasma Physics, a “plasma” is a state of matter similar to gas in which a certain portion of the particles are ionized. Various plasma diagnostic methods have been employed in experimental plasma physics to characterize the physical properties of plasma, such as density, temperature and collision frequency. Langmuir probe, plasma spectroscopy, microwave, optical interferometry and Thomson scattering are commonly used to measure plasma density.
One type of plasma typically encountered is laser-pulse induced plasma. Laser-pulse-induced plasma is transient in nature with a fast temporal evolution of parameters. A detailed understanding of the fast dynamics of laser-induced plasma is of great importance to potential applications in plasma chemistry, high harmonics generation, wakefield acceleration, and self-guided filament propagation. The plasma inside the laser filaments has been characterized by several investigations using the methods described above. For example, the electric conductivity measurement provides direct density information of the plasma channel with a temporal resolution of nanoseconds. Also, optical interferometric methods are capable of resolving the plasma dynamics with sub-picosecond resolution.
However, a need exists to provide tools for analysis of plasmas, for example, the transient nature plasmas, in particular, to analyze laser-pulse-induced plasmas.